| Research Abstract |
Vitronectin (VN) is a multifunctional glycoprotein involved in tissue remodeling. Previously, we reported that glycosylation of VN significantly changes and enhances the collagen-binding activity^1). In this study, the effect on tissue lytic system and the cell-spreading activity of VN was focused.
Rat VNs were purified after urea-denaturation form plasma 24 hours after partial hepatectomy (PH), sham-operation (SH) and non-operation (NO). The binding of PH-or SH-VN to stabilize plasminogen activator inhibitor-1 (PAI-1) decreased to 1/3 and 2/3, respectively, of that of NO-VN. The uPA-binding of both PH-and SH-VNs increased to 2 times of that of No-VN. Consequently the activites of uPA were increased in the presence of SH-or SH-VN compared with NO-VN. In contrast, deglycosylation of VNs by enzyme treatments enhanced both PAI-1 and uPA binding so that the resultant uPA acitivity was unchanged suggesting that the cach ligand-binding of VN is influenced complexly with the innerglycan structures.
The cell spreading activity on VN substrate differed by the kind of cells The spreading of BHK on desialylated VN decreased to 1/2 of that of control VN, indicating that the cell-spreading activity is significantly affected by sialylation state of VN. However, on the VNs during liver regeneration, BHK cells exhibited slightly decreased spreading on SH-VN but similar spreading on PH-VN and NO-VN.
PH-VN induced the enhanced uPA activity, which would promote plasmin generation. Therefore, the change in glycosylation of VN contributes to tissue remodeling by enhancing tissue lysis at the initial stage of liver regeneration.
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